For example, in a vehicle-mounted fuel cell system, hydrogen gas in a tank is supplied to a fuel cell. In the fuel cell, the hydrogen gas reacts with oxidized gas and is thus consumed. Thus, power is generated and used for driving. If the amount of hydrogen gas remaining in the tank decreases as a result of the consumption, the vehicle stops off at a hydrogen station so as to be filled with hydrogen gas from the hydrogen station.
Here, when hydrogen gas is fed, that is, emitted from the tank, the pressure and temperature in the tank decrease. On the other hand, when hydrogen gas is filled into the tank, the pressure and temperature in the tank increase. Furthermore, a tank of this kind is generally configured such that a gas-impermeable liner is covered, on an outer peripheral surface thereof, with a reinforcement layer offering pressure resistance (see, for example, Patent Document 1). For example, the reinforcement layer is formed of CFRP wound around the outer peripheral surface of the liner by a filament winding method or the like.